A 1.5–4 K detachable cold‐sample transfer system: Application to inertially confined fusion with spin‐polarized hydrogen fuels

A compact cold‐transfer apparatus for engaging and retrieving samples at liquid‐helium temperatures (1.5–4 K), maintaining the samples at such temperatures for periods of hours, and subsequently inserting them in diverse apparatuses followed by disengagement, is described. The properties of several thermal radiation‐insulating shrouds, necessary for very low sample temperatures, are presented. The immediate intended application is transportable target shells containing highly spin‐polarized deuterons in solid HD or D2 for inertially confined fusion experiments. The system is also valuable for unpolarized high‐density fusion fuels, as well as for other applications which are discussed.